FORT WORTH, Texas — Aaron Alexis was so unhappy with his life in America — where he was beset by money woes and felt slighted as a veteran — that he was “ready to move out of the country” last year, a friend said Tuesday.

“He was tired of dealing with the government,” said Kristi Suthamtewkal, whose husband owns the Thai Bowl Restaurant in Fort Worth, where Alexis worked in exchange for room and board.

But instead of leaving the U.S., the former Navy reservist relocated from Texas to Virginia, where an IT company called The Experts put him on a government contract at the Washington Navy Yard.

A day after Alexis, 34, gunned down 12 people at the yard, new details emerged of his troubled past — from his preoccupation with 9/11 to recent mental problems that included hearing voices in his head.

Investigators said Tuesday that a preliminary probe has turned up no evidence that Alexis participated in rescue operations at Ground Zero, as his father once told police.

He was, however, employed as a clerical worker at the Borough of Manhattan Community College, in the shadow of the Twin Towers, when they were destroyed on Sept. 11, 2001.

“He talked about 9/11 and where he was and how the buildings had collapsed and he couldn’t believe that…and how he was upset with the terrorists for taking innocent lives,” Suthamtewkal said.

Melinda Downs, who took in Alexis after he moved out of the Suthamtewkals’ house last year, said he told her he suffered from post-traumatic stress after “surviving 9/11 in New York.”

And when Alexis was arrested in Seattle in 2004, for shooting at a parked car in what he called an “anger-fueled blackout,” he brought up 9/11 during his interrogation and “how those events had disturbed him,” police said.

Three years after that arrest, Alexis enlisted in the Navy Reserves and served as an aviation electrician’s mate — a third-class petty officer — before he was given an honorable discharge in January 2011.

Military officials acknowledged that Alexis had disciplinary issues including absence without permission, insubordination and disorderly conduct.

Among the problems: an arrest in September 2010 by Fort Worth police after he accidentally fired a bullet into the apartment above him while he was cleaning a gun with slippery hands. Prosecutors determined that there wasn’t enough evidence to bring a recklessness case.

After his discharge, Alexis began an online course in aeronautics with Embry-Riddle Aeronautical University. He worshiped at a Buddhist Temple and was befriended by Suthamtewkal’s husband, Oui, who ” took him under his wing and took care of him.”

He was given a room at their house in exchange for help at the restaurant, where he was one of the more popular waiters.